Every fee is on the screen before you confirm. Nothing is worked out afterwards.
Ways to be seen
Fees
This is a private billing practice. Your fee and your Medicare rebate are both displayed on HotDoc before you confirm your booking, and they are kept current.
Why there is a gap
Medicare rebates have not kept pace with the cost of providing care. Rebates were frozen from 2012, and since indexation resumed they have typically risen more slowly than inflation, so the gap between the rebate and the cost of delivering an unhurried appointment tends to widen each year.
Rebates are also proportionally higher for short consultations than long ones. A rebate for a 30 minute appointment is not double the rebate for a 15 minute appointment, which is why longer appointments carry a larger gap.
If your appointment runs long
If you booked a standard face to face appointment and it runs past a set time, a higher Medicare rebate applies, worth around $50 more. The total you pay upfront increases by about the same amount, and your rebate increases to match. Your out-of-pocket cost stays exactly what HotDoc quoted you.